With the rapid development of the electronics industry, electronic products tend to be light, thin, short, high density, security and high functionality, requiring electronic components to have higher signal transmission speed and transmission efficiency, which makes higher performance requirements on the printed circuit board as the carrier. Due to high speed and multi-functionalization of electronic product information processing, the application frequency is continually increased, and 3 GHz or more will gradually become mainstream, therefore, besides maintaining the higher requirements on heat resistance of laminate materials, dielectric constant and dielectric loss value will be required to be lower and lower.
The current traditional FR-4 is difficult to meet the application demand on high frequency and rapid development of electronic products. Meanwhile, the substrate material no longer plays the traditional mechanical support role, and will become together with the electronic components an important way to improve product performances for PCB and designers of terminal manufacturers.
Because high Dk will slow down the signal transmission rate, and high Df will convert the signal partly into heat loss in the substrate material, high-frequency transmission with low dielectric constant and low dielectric loss, especially the development of halogen-free high-frequency plates, has become the focus of copper clad laminate industry.
At present, halogen-containing flame retardants (especially brominated flame retardants) are widely used in polymer flame retardant materials, and play a better flame retardant effect. However, it is concluded after the in-depth study of the fire scene that, although the halogen-containing flame retardant has a better flame retardant effect and a small addition amount, the polymer material containing the halogen-containing flame retardant will produce a lot of toxic and corrosive gas and smoke which suffocate people, thereby being more harmful than the fire itself. As a result, the development of the halogen-free flame retardant printed circuit boards has become a key point in the industry with the formal implementations of the EU Waste Electrical and Electronic Equipment Directive and the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment on Jul. 1, 2006. The CCL manufacturers have launched their own halogen-free flame retardant copper clad laminate.
In order to solve the above-mentioned problems, CN101796132B discloses a composition comprising an epoxy resin, a low molecular weight phenol-modified polyphenylene ether and a cyanate. Such epoxy resin composition has excellent dielectric properties, and is capable of maintaining flame retardancy and has high heat resistance. However, brominated flame retardant is used in the epoxy composition for flame retardancy. Although such composition has excellent comprehensive performance, the flame retardant containing bromine component are easy to cause environmental pollution during the product manufacture, use or even recovery or disposal, and are hard to meet the requirements of the environmental protection.
CN103013110A discloses a cured product comprising a cyanate, styrene-maleic anhydride, a polyphenylene ether, and bismaleimide, and the use of phosphorus-nitrogen compound as flame retardant can achieve low dielectric constant, low dielectric loss, high heat resistance and high flame resistance. However, bismaleimide has a high curing temperature, and the cured product is more brittle, resulting in many deficiencies during the processing and use.
Therefore, it is an urgent problem to be solved how to produce a prepreg and laminate having low dielectric constant, low dielectric loss and excellent chemical resistance.